The aim of this study was to determine the behaviors in response to tuberculin skin test (PPD) conversion and the reasons for starting or not starting treatment for latent tuberculosis infection (TILT) among medical students at a university in Lima, Peru. A total of 548 participants completed a questionnaire; of them, 6.7% tested positive on university admission and 11.1% were recent converters. A total of 55.7% did not start TILT and had no explanation. Of the recent converters, most students who did start TILT were >22 years old (p = 0.01) and correctly answered general knowledge questions (p = 0.04). It is important to note that the PPD conversion rate was higher than that reported in the literature and that most students did not follow the treatment prophylaxis because of a lack of information.